|The land for Fort Foster, located on the southwest tip of Gerrish Island in Kittery, Maine, was acquired by the federal government in 1872, making this fort the last of the "old" forts that were built in the Portsmouth area. |
In 1899 construction was started on new concrete batteries to help protect the Naval Shipyard in the aftermath of the Spanish-American War. In 1900 the site was officially named Fort Foster, after Civil War era Brevet Major General John G. Foster of New Hampshire, and the post became a sub-post of Fort Constitution.
In 1905 - 1907, the fort was officially garrisoned by the 124th Company, U.S. Coast Artillery Corps, and then afterwards, except during World War I (1917 - 19), was never actually manned by more than a caretaker unit from Portland, Maine (Battery E, 8th Coast Artillery Regiment (Harbor Defense), U.S. Army) until World War II.